In some applications where files of information or data is stored and manipulated by a computer, the order of the presentation of the files is important. For example, in a system which stores and manipulates architectural and construction drawings and other data, with each drawing constituting a separate data file, the precise order of the presentation of the files is important, as is the ability to change the order and to incorporate new files into an existing order.
One way, known in the art, to construct an ordering of files is to create an index file. The index file is a list of pointers to the data files. A change made to the index file will change the order of presentation of the data files. Disadvantages of using an index file are that the separate index file has to be maintained and that corruption of the index file will hurt the usefulness of the system. Also, in an environment where many concurrent users are accessing, changing, and reordering data files, such as in an Internet-based system, concurrent updating of an index. file is not possible in some cases and presents difficulties in others.
Our invention overcomes the problems of the prior art by providing a method for defining a sequence of files by placing a numerical value in a header of the file. The numerical value assigned to each file is obtained in such a way as to substantially decrease the likelihood that a reassignment of all numerical values will become necessary.